In digital camera systems, such as CMOS image sensor-based systems, the pixel array is generally read out in what is called a “rolling shutter” method. In rolling shutter, the exposure and reading of the array begins at the top of the array for each frame and proceeds to roll down the array throughout the frame capture interval of time. Because of this, action captured at the beginning of a frame capture interval of time is captured only at the top of the frame (scene), action captured in the middle of a frame capture interval is captured in the center of the frame and action captured at the end of the frame capture interval is captured at the bottom of the frame. Thus, when an object moves during the frame capture interval (or when the camera moves during the same), the captured reproduction of the object may be a slanted or swizzled version of the object, skewed relative to the motion between the object and the camera over the total frame capture interval. These effects are referred to herein as “rolling shutter artifacts”.
Rolling shutter artifacts are undesirable due to the distortion they impose on the object within a captured image. One method to overcome this issue is to use a global shutter, wherein the entire image sensor array is exposed at once, then blinded (either via mechanical shutter or electrically-controlled light sensitivity or other). The pixel data is then read out in a rolling manner. This approach is challenging to implement in small camera systems and/or cameras with small image sensor pixels. Another method to minimize rolling shutter artifacts is to capture the image frames at very high rates. While this minimizes the rolling shutter time (and thus minimizes rolling shutter artifacts), it uses much more power than running systems at nominal frame rates and can create bottlenecks at various points within the image capture architecture (such as at an image sensor and/or image processor) unable to keep up with such a rapid rate of frame capture. It is thus desirable to capture images with minimized rolling shutter artifacts without imposing the size, weight, cost, and/or power and performance requirements of the solutions listed above.